Safer train journey by space tech

Wind tunnel developed by German company Hyperschall Technologie Göttingen. Credit: HTG

Wind tunnel developed by German company Hyperschall Technologie Göttingen. Credit: HTG

Good train brakes are crucial for safe rail journeys. In Germany, they are now checked daily using advanced technology that helps spacecraft return safely to Earth.

Railway personnel at Deutsche Bundesbahn simply connect the new automatic tester to the hydraulic brake clutches and select the train type. The computer does the rest via a special sensor – a spin-off from spacecraft reentry research – to verify quickly if the brakes are OK or if they are leaking air.

The device draws on the special technique developed to determine the best trajectory for a spacecraft to enter Earth's atmosphere. The result is more reliable testing which in the end guarantees safer train journeys.

It all started over 20 years ago when German company Hyperschall Technologie Göttingen (HTG), a specialist in aerodynamics, wanted to 'fly' models of reentry capsules in their hypersonic wind tunnel.

"We can simulate the aerodynamics up to nine times the speed of sound of space capsules entering the atmosphere," said HTG's Prof. Georg Koppenwallner.

"The maximum temperature increase as a result of the air flow can be determined by measuring the volume of the flow."

Through careful design, the company developed flow meters for these tests that provided very precise measurements.

In Germany, Deutsche Bundesbahn now uses an automatic test system to check the hydraulic brakes on their trains. The tester is based on special sensor technology developed for ESA and DLR testing of reentry spacecraft research. Credit: Deutsche Bahn AG/U. Miethe

"For the past two decades, HTG has been among ESA's most competent partners in aerothermodynamics. Its founder, Prof. Koppenwallner, is recognised worldwide for his expertise," says Jan Thoemel, ESA Expert Project Scientist.